Acid formation from various sulfonates in a chemical amplification positive resist

The quantum yield for acid generation from alkyl and arylsulfonic acid esters of pyrogallol was measured in resist films composed of a sulfonate, tBOC‐BA, and novolak resin. It was found that the quantum yield increases with decreasing molecular size of the sulfonyl group, which can explain the differences in sensitivity of the resist systems. Methanesulfonic acid esters of various phenol derivatives were synthesized to see the effect of backbone structure on the efficiency of acid generation. The sensitivity measurement of resists containing these sulfonates indicates that the number of sulfonyloxy groups bonded to a benzene ring is important. The higher number of the sulfonyloxy groups gives a higher efficiency of acid generation.